How can I exit [NSRunLoop runUntilDate]?

I am writing an application which has to communicate with a device connected via USB. The app sends and receives data in turns from the device on a fixed timing. All Rx/Tx happens in a separate thread because otherwise the UI would be blocked. The basic structure looks basically like this. (autorelease pools and stuff omitted) ``` -(void)comThread:(id)arg { while(state == kIsConnected) { // let timers run [runLoop runUntilDate:[NSDate distantFuture]]; // handle data if(rxTxState == kRx) { // do some stuff to pass data to upper layers rxTxState = kTx; } if(rxTxState == kTx) { // do some stuff to send data rxTimeoutTimer = [NSTimer scheduledTimer....]; } } } ``` After sending data, the app waits for either data to be received or the `rxTimeoutTimer` to fire which leads to retransmission of the packet. The rx-operation works since the underlying layers use async system calls and calls a rx-handler which look basically like this. ``` -(void)receiveData:(NSData*)data{ [rxQueue addObject:data]; [rxTimeoutTimer invalidate]; // cancel timeout } ``` Is there an (easy) way to make the `[runLoop runUntilDate:]` exit from `receiveData:`? The Apple docs say that removing all timer sources does not guarantee the RunLoop to exit. I read something about calling `performSelector:onThread:...` but it either did not work or I did not get the point. Thanks.